The 99 equal temperament, often abbreviated 99-tET, 99-EDO, or 99-ET, is the scale derived by dividing the octave into 99 equally-sized steps, where each step represents a frequency ratio of 12.1212 cents. It is a very strong 7-limit (and 9 odd limit) temperament, but extending it to the 11-limit requires choosing which mapping one wants to use, as both are nearly equally far of the mark. It tempers out 3136/3125, 5120/5103, 6144/6125, 2401/2400 and 4375/4374, and supports hemififths, amity, parakleismic, hemiwürschmidt and ennealimmal temperaments, and is pretty well a perfect tuning for hendecatonic temperament. It has a sound defined by the slight sharpness (1.075, 1.565, 0.871 cents) of its 3, 5, and 7.

Using the patent val, <99 157 230 278 342|, 99 is the optimal patent val for the rank four temperament tempering out 121/120; zeus, the rank three temperament tempering out 121/120 and 176/175; hemiwur, one of the rank two 11-limit extensions of hemiwürschmidt; and hitchcock (11-limit amity), the rank two temperament which also tempers out 2200/2187. Using the <99 157 230 278 343| ("99e") val, 99 tempers out 896/891, 243/242, 441/440 and 540/539, and is an excellent tuning for the 11-limit version of hemififths temperament. Hence 99, in spite of the fact that it tunes 11 relatively badly, is an important 11-limit tuning in more than one way.

Scales

tutone6
tutone7
tutone13
zeus7tri
zeus8tri

Music in 99edo

Nonaginta et Novem play by Gene Ward Smith
Benny Smith-Palestrina in zeus7tri

Intervals

Degrees	Cents Value
1	12.121
2	24.242
3	36.364
4	48.485
5	60.606
6	72.727
7	84.848
8	96.97
9	109.091
10	121.212
11	133.333
12	145.455
13	157.576
14	169.697
15	181.818
16	193.939
17	206.061
18	218.182
19	230.303
20	242.424
21	254.545
22	266.667
23	278.788
24	290.909
25	303.03
26	315.152
27	327.273
28	339.394
29	351.515
30	363.636
31	375.758
32	387.879
33	400
34	412.121
35	424.242
36	436.364
37	448.485
38	460.606
39	472.727
40	484.848
41	496.97
42	509.091
43	521.212
44	533.333
45	545.455
46	557.576
47	569.697
48	581.818
49	593.939
50	606.061
51	618.182
52	630.303
53	642.424
54	654.545
55	666.667
56	678.788
57	690.909
58	703.03
59	715.152
60	727.273
61	739.394
62	751.515
63	763.636
64	775.758
65	787.879
66	800
67	812.121
68	824.242
69	836.364
70	848.485
71	860.606
72	872.727
73	884.848
74	896.97
75	909.091
76	921.212
77	933.333
78	945.455
79	957.576
80	969.697
81	981.818
82	993.939
83	1006.061
84	1018.182
85	1030.303
86	1042.424
87	1054.545
88	1066.667
89	1078.788
90	1090.909
91	1103.03
92	1115.152
93	1127.273
94	1139.394
95	1151.515
96	1163.636
97	1175.758
98	1187.879
99	1200